@GromNaN: Am I correct in assuming that defining a service here still requires it to be enabled via the formatter option for a handler definition? Per the custom formatter docs.

I expect this eventually would warrant changes to https://github.com/symfony/symfony-docs/blob/7.3/logging/formatter.rst as well to list this in the documentation.

Looking at Seldaek/monolog@c04d39d, the MongoDBFormatter is the one by default since Monolog 2.

We can create a new mongodb type handler that uses the service MongoDBFormatter by default as handler and passes the constructor options ($maxNestingLevel and $exceptionTraceAsString). Similar to this: